Propulsion systems for vehicles in use today consist of wheels, tracks and, in rare cases, worms or legs. They are very efficient devices, but are incapable of automatically changing the speed of a vehicle without changing gears of the transmission or the speed of the motor. Most power sources can operate only over small speed range with good economy and power. As a result, a large number of gear changes are required for efficient operation. The present automatic and manual transmissions in use attempt to maximize operating economy and power through a constant maintenance of power source rotational speed at the top of the power curve. These transmissions do not have high efficiency or smooth operation because they must have stepped speed ratio changes. Existing designs for continuously variable transmission lack efficiency, simplicity of operation, power transmission capability or operating speed range.
Turning one or two pairs of wheels through a complicated linkage system or pivoting the front of the vehicle against the rear commonly accomplishes the change of direction for wheeled vehicles. For vehicles on tracks or worms it is done through braking or reversing the track or worm on one side.
In all cases existing systems consist of either a complicated mechanical arrangement, resulting in high cost and maintenance, or require substantial expenditure of available power, decreasing operating efficiency.
The object of this invention is an improved vehicle""s propulsion system. The proposed propulsion system takes advantage of the fact that a wheel in the shape of a hemisphere rotating around its polar axis has larger length of circumference at its major diameter than close to its tip. The radius of a hemisphere is a constant, therefore the transition from the major diameter to a minor diameter produces step less length of circumference change without changing the point of engagement between the hemisphere wheel and the ground. The hemisphere wheel on each side of the vehicle thus would be mounted on the bearing. The inside race of the bearing would have two pivot points inside the hemisphere""s major diameter allowing the wheel to swing around a mounting fork. The fork is attached to the body of the vehicle or is a part of the suspension. The center of the hemisphere wheel would be connected to the driving shaft through a constant velocity device (double universal joint, flexible shaft or similar). Alternatively, each wheel can have a motor mounted on the inside race of the bearing, the shaft of the motor is then connected to the hemisphere wheel. A control lever would have a joint attachment to the inner race of the wheel bearing, perpendicular to the pivot points. Movement of the control lever would swing the hemisphere wheel around the pivot points, changing the diameter of the wheel engaged with the ground. The positions of the control levers would thus determine the vehicles speed and/or direction. By tilting the pair of hemisphere wheels in opposite directions against the pivot points of the corresponding mounting forks, the vehicles speed would be increased or decreased.
A unidirectional swing of the pair of wheels would produce a vehicles change of direction. A four-wheel vehicle can have one pair of hemisphere wheels and another pair of regular wheels or, for increased mobility, two pairs of hemisphere wheels. By swinging one pair of hemisphere wheels in opposite direction from the second pair the front and rear of the vehicle would be directed in opposite directions thus producing an extremely small turning radius. A vehicle can have multiple pairs of hemisphere wheels. The control levers for a pair of hemisphere wheels can be separate, individually controlling each wheel, or joined, primarily for directional control, or have both joined and individual control, allowing for multiple control schemes of speed and direction.
It is therefore an object of the present invention to provide an improved vehicle""s propulsion system which can be easily and economically produced, simple in principal, convenient in operation, sturdy in construction, highly efficient, long lasting and capable of operating under wide range of power and speed.